Commercially available IBM (TM) PS/2 (TM) personal computers constructed in accordance with Micro Channel (TM) architecture, are provided with a Programmable Option Select (POS) function which is used to define or provide settings for the assignment of system resources to a system board and various adapters. The POS Function is generally described in "IBM Personal System/2 Hardware Interface Technical Reference", First Edition (May 1988), published by International Business Machines Corporation, to which reference may be had for a more detailed description thereof.
Adapters provide the means by which various data processing devices or optional features can be connected into and operated as part of a personal computer system. Examples of such features are displays, printers, scanners, etc. In accordance with the above mentioned architecture, an adapter has a group of programmable registers, known as the POS registers, which, by convention, must store or contain predetermined POS information. Two registers store an adapter ID that uniquely identifies the specific adapter relative to other adapters. Four additional registers store an adapter card enabling/disabling bit and option select data, and two additional registers store subaddress extensions. Before an adapter can be used, an adapter description file (ADF) must be created by the supplier of the adapter. The ADF contains data necessary for the operation of the adapter and its related option or device, the data defining the resources the adapter can use, and the associated POS settings that indicate the resource assignment.
Each system includes a Reference Diskette containing System Configuration utilities or programs that identify the installed hardware and interpret the system resources (I/O ports or address space, memory address space, interrupt levels, and arbitration levels) for each device. Normally, the files on the Reference Diskette are copied onto a backup copy which is then used to configure the system. As options are added to the system, the files needed for configuration are merged onto the backup copy. During configuration, certain files are needed, the files being an ADF and any necessary Adapter Description Program (ADP). An option diskette is supplied for each adapter and contains the necessary ADF and ADP. Such files are merged onto the backup copy before a new adapter is installed.
An ADF contains various fields of information including the following: adapter ID; adapter name; the number of POS registers to be included; an optional field indicating that an adapter option will be specified next; a prompt keyword; a choice keyword including the choice name, a POS setting which programs the adapter appropriately, and a resource setting which identifies the resources used for the particular choice; and a help keyword.
In accordance with the prior art, a system such as described above has to be configured when the system is setup for the first time and thereafter each time an adapter is added to, removed from, or moved within the system. When the system is being configured, POS data is stored in a non-volatile memory. Thereafter, whenever the system is turned on, a Power On Self Test (POST) is performed during which the POS data is retrieved from the non-volatile memory and is used to establish the system configuration. Such test also recognizes when an adapter card is added to, removed from, or moved within the system. When this occurs all other feature cards (such as the disk controller adapter) are disabled in the system, and a display message is sent to the operator or user indicating that the system must be reconfigured before it can be further operated.
The obvious drawback of this existing POS sequence is that the addition of any new card to the system (or removal from the system, or simply a change of slot) requires that the system be reconfigured before the system can again be operational. For example, the removal of an asynchronous communications attachment card will cause the hard disk subsystem to be disabled (preventing operating system initialization from the hard disk). Disabling all other devices may not be necessary and may not provide the user with the maximum function possible. This restriction can be removed by the implementation of the invention which allows the system to be operated with the features that are not disabled.
The foregoing describes in general terms the prior art being improved upon, and such prior art is also believed to be the most pertinent or relevant to the invention. However, certain prior art items are also known which describe inventions useful in configuring data processing systems. U.S. Pat. No. 4,070,704- Calle et al, for AUTOMATIC RECONFIGURATION APPARATUS FOR INPUT/OUTPUT PROCESSOR, discloses a system in which all possible memory, I/0, and processor combinations are attempted, in order to automatically reconfigure the system when a bootstrap failure occurs during system startup.
IBM TDB Vol. 20, No.9, February 1973, pp. 3501-3502, discloses a modular relocate scheme in which RAMS are partitioned on a separate card, module, or chip in such a way that a processor will operate with or without a card, module, or chip.